Ayra + Phantom Speed

This thing came out like 2-3 months ago, dude. Yes, it's been confirmed. The thing doesn't actually give you +5 Spdd, otherwise it would be silly overkill and everyone would be using it (contrary to ever seeing it, like, ever). What it does, is that it only really affects skills that happen to address the *relation between* your Spd stat and your opponent (basically, at the top of my mind, Water and Windsweep skills).

That's about it.

Phantom SPD does work with her sword's ability, but wont boost her special damage or help you double. So it doesn't actually help you that much.
So you are really better off with ATK or SPD seals depending on IV.